The bride-to-be later posted an "update" of her upcoming nuptials on her website.
"William and I are overwhelmed by all of your warm wishes. Thank you so much for sharing in this special moment :-)," Conrad added.
The reality TV star apparently has the support of all her friends and family.
"Everyone is so happy for her. He's such a great guy. They are perfect for each other!" a source toldPeople.
Conrad began dating Tell, a law student, last year.
Conrad left The Hills -- which MTV ended after six seasons in 2010 -- during its fifth season in 2009, ending a five-year period in which she starred on both The Hills and its Laguna Beach predecessor, which followed her as a 17-year-old high school senior in Laguna Beach, CA.
(Photo credit MTV)
DISCUSS AND COMMENT ON THIS STORY Reality TV World now offers Facebook Comments on our stories. To post a comment, log into Facebook and then 'Add' your comment. To report spam or abuse, click the 'X' in the upper right corner of the comment box. Get more Reality TV World! Follow us on Twitter, like us on Facebook or add our RSS feed.